1. Field of the Invention
This invention relates generally to trocars for use in endoscopic surgery, and, more particularly, to locking devices for securing in position an instrument inserted through a trocar into a body cavity, so as to prevent movement of the instrument.
2. Description of Related Art
As is well known, surgical devices, such as trocars, are widely used in endoscopic surgery. Trocars are devices that are used to provide access to a surgical site within a selected cavity in a patient's body. A trocar is typically inserted through a small skin incision by pressing the distal end of the trocar against the outer skin of the patient with sufficient force applied to the trocar handle, so that the piercing tip of an obturator effectively penetrates the patient's skin and underlying fat tissue, fascia, muscle and into a selected internal cavity. The trocar obturator is removed, and the trocar cannula is then used as a passageway to and from the patient's body cavity. During many procedures, a number of trocars are required so that a number of passageways are formed into the selected body cavity, to enable a surgeon to concurrently use an endoscope and one or more other devices inserted into the body cavity.
An example of a known trocar is shown in U.S. Pat. No. 5,256,149 to Banik et al. This patent discloses a trocar constructed from a transparent plastic material, and includes a trocar cannula with a cannula handle, a cannula tube and a trocar obturator passing through the handle and tube. The device also includes a gas inlet, having a valve thereon to enable a gas to be used to insufflate and desufflate a body cavity into which the trocar cannula has been inserted and is held, as well as a handle to operate an interior flap valve to release gas pressure in the trocar. After the obturator is used to pierce a person's body and form an opening into an underlying body cavity, the trocar cannula may be threaded into the opening formed into the body cavity with a stability thread to aid in securing the trocar cannula in place. The obturator is removed from the trocar cannula, and an instrument, such as an endoscope, an endoscopic needle grasper, a holding device, a manipulating device, or the like, may be inserted through the trocar cannula into the body cavity.
During many types of surgery, a number of trocars are inserted so that there are a number of passageways into the selected body cavity. One or more of these passageways may be used to move or position an organ if a further portion thereof must be seen or operated on. In addition, the organ may cover or block another organ, which needs to be examined or operated on. This is usually accomplished by the insertion of a grasping or manipulating device or instrument, into a passageway in one of the trocars. However, the grasping or manipulating instrument is usually loosely aligned in the trocar passageway, and must be held in position or somehow secured, so that any organ, or the like, that is pressing against or supporting, does not move or shift. Since the surgeon and/or assistant must concentrate on specific steps and requirements during a surgical procedure, and often need both of their respective hands, a holding means or another person must help to hold or support the grasping or manipulating device. Often, however, it is left to the surgeon or assistant to try to hold the instrument steady by the use of a surgical clamp between the instrument and a surgical drape on the patient, or somehow jury-rig a means to hold or support the instrument. For numerous reasons, surgeons and their assistants have difficulty in fully or properly holding or supporting such grasping or manipulating device, and problems have occurred. Therefore, a need exists for a simple and effective means for holding a grasping or manipulating device or instrument in place in a trocar during surgical procedures, such as endoscopic surgery.
In my U.S. Pat. No. 5,662,613 ("'613"), entitled "Endoscopic Instrument Lock", there is described and shown a locking device for use in holding an instrument in place in a trocar. This locking device is preferably metallic, and includes an enlarged head that may be easily grasped and recognized by a surgeon during surgery. The device has an elongated shaft portion with self-taping threads formed thereon, secured to the enlarged head. The outer end of the elongated shaft is blunt and soft to prevent damage or marring of an instrument against which it is pressed. The elongated shaft is inserted into the existing gas opening in the wall of the trocar and the enlarged head turned so that the self-tapering threads are threaded into the existing gas opening to lock the device into position with the blunt, soft end against an instrument. The enlarged head is preferably knurled, roughened or serrated to enable the locking device to be easily grasped and turned by the fingertips of a user. The spherical head is also preferably made from or covered with a phosphorescent material so as to be more easily seen in low lighting conditions. Although this locking device has provided significant improvement in the art, there is a possibility that if it is carelessly handled or manipulated, foreign or toxic material might be dislodged or inserted into the gas opening and enter a body cavity of a patient.
Furthermore, the locking device of the '613 patent must be stored before or after use, and is not always immediately available for use, unless placed in the gas opening of the trocar or trocars, before, during or after being inserted into a body cavity.
Therefore, there still exists a need in the art for easy to use and readily available locking devices for instruments inserted into a trocar, and, in particular, locking devices that are not easily laid aside or misplaced.